My Labidochromis caeruleus are really washed out, and not at all like the very bright yellow ones I saw in the shop. Why are they so bland?

Labidochromis caeruleus are one of the most placid mbuna species, and crabro and callainos can be rather aggressive. Pseudotropheus sp. “kingsizei”, which is now called Pseudotropheus pulpicans, also has a tendency to become hyper-dominant.

Males often take over the whole tank and develop outstanding colours, but suppress other fish and cause them to look far less colorful than they could. So one reason your caeruleus look so drab is because the other aggressive species you’re keeping are a bit too boisterous.

Also try algae-based Spirulina foods, which are natural colour enhancers, and check you have males and females, as females are more pale, with a whitish belly. Males have stronger colouration with black edges to the fins.

You can keep these species together, but you’ll get better results and have more colourful fish if you keep them with some more placid species, like other Labidochromis, smaller Pseudotropheus such as saulosi and demasoni or Iodotropheus sprengeri.

More aggressive species can also lose their coloration when suppressed by more dominant fish. This is something particularly noticeable in the blue-black barred Pseudotropheus and Metriaclima species.

If you have these in your tank and want them to look their best, ensure that they’re the most dominant fish in the tank and won’t be dominated by other more aggressive species.

This item was first published in the August 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.